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Ford Lindgreen posted an update 5 hours, 47 minutes ago
We demonstrate a host-guest molecular recognition approach to advance double electron-electron resonance (DEER) distance measurements of spin-labeled proteins. We synthesized an iodoacetamide derivative of 2,6-diazaadamantane nitroxide (DZD) spin label that could be doubly incorporated into T4 Lysozyme (T4L) by site-directed spin labeling with efficiency up to 50% per cysteine. learn more The rigidity of the fused ring structure and absence of mobile methyl groups increase the spin echo dephasing time (Tm) at temperatures above 80 K. This enables DEER measurements of distances >4 nm in DZD-labeled T4L in glycerol/water at temperatures up to 150 K with increased sensitivity compared to that of a common spin label such as MTSL. Addition of β-cyclodextrin reduces the rotational correlation time of the label, slightly increases Tm, and most importantly, narrows (and slightly lengthens) the interspin distance distributions. The distance distributions are in good agreement with simulated distance distributions obtained by rotamer libraries. These results provide a foundation for developing supramolecular recognition to facilitate long-distance DEER measurements at near physiological temperatures.Amorphous indium-gallium-zinc oxide (a-IGZO) films, which are widely regarded as a promising material for the channel layer in thin-film transistors (TFTs), require a relatively high thermal annealing temperature to achieve switching characteristics through the formation of metal-oxygen (M-O) bonding (i.e., the activation process). The activation process is usually carried out at a temperature above 300 °C; however, achieving activation at lower temperatures is essential for realizing flexible display technologies. Here, a facile, low-cost, and novel technique using cellophane tape for the activation of a-IGZO films at a low annealing temperature is reported. In terms of mechanochemistry, mechanical pulling of the cellophane tape induces reactive radicals on the a-IGZO film surface, which can give rise to improvements in the properties of the a-IGZO films, leading to an increase in the number of M-O bonds and the carrier concentration via radical reactions, even at 200 °C. As a result, the a-IGZO TFTs, compared to conventionally annealed a-IGZO TFTs, exhibited improved electrical performances, such as mobility, on/off current ratio, and threshold voltage shift (under positive bias temperature and negative bias temperature stress for 10,000 s at 50 °C) from 8.25 to 12.81 cm2/(V·s), 2.85 × 107 to 1.21 × 108, 6.81 to 3.24 V, and -6.68 to -4.93 V, respectively.Adopting the mixed ligands approach, two water-stable Zn5 cluster-based MOFs, [Zn10(TZ)12(TADIPA)2(DMF)4]·DMF·6H2O (JLU-MOF66) and [Zn10(TZ)12(TPTA)2(DMA)2]·2DMA·4H2O (JLU-MOF67), have been constructed (H4TADIPA = 5,5′-(1H-1,2,4-triazole-3,5-diyl)diisophthalic acid, H4TPTA = [1,1’3′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid, and HTZ = 1H-[1,2,3]triazole). Both compounds with [Zn5(TZ)6] clusters exhibit extraordinary stability (pH = 2-11) and selectivity of C3H8/CH4 (308 for JLU-MOF66, and 287 for JLU-MOF67). Compared to JLU-MOF67, JLU-MOF66 with functional groups exhibits higher CO2 and C2H2 uptake capacity and excellent selective separation for C2H2/CH4 (86, 11). Such high separation and chemical stability render them as promising materials for industrial applications.The thermal conductivity (κ) of glasses is known to always be lower than that of their corresponding crystals due to the stronger phonon-phonon scattering in the former. However, it is unknown whether this relation holds for metal-organic frameworks. Here, we report our discovery of an inverse relation in κ between glass and crystal for two zeolitic imidazolate frameworks (ZIFs), ZIF-4 and ZIF-62, that is, melt-quenched ZIF-4 and ZIF-62 glasses possess higher thermal conductivities than their crystalline counterparts. We find that the ZIF crystal pellets exhibit ultralow κ (∼0.1 W m-1 K-1) and that the higher κ of the ZIF glasses is due to the collapse of internal cavities and higher atomic number density in the latter. For other systems like oxides, vitrification causes higher free volume, but the opposite is found for the ZIFs, that is, lower free volume owing to the partial collapse of the crystalline framework upon melting.Indole alkaloids are important natural compounds with interesting bio-activities that can be found in various species belonging to the Amaryllidaceae, Apocynaceae, or Strychnaceae families. Although these compounds have different connections, substituents, and functionalities, their main core can be produced via the formation of a common functionalized tetracyclic subunit, which is rapidly obtained by an oxidative de-aromatization process mediated by a hypervalent iodine reagent from an inexpensive phenol containing a lactate moiety as the chiral auxiliary. A subsequent stereoselective aza-Michael addition and an intramolecular Heck-type reaction lead to the formation of a common key intermediate. This approach provides a solid foundation for the further elaborations of several natural products. The asymmetric syntheses of (-)-strychnopivotine and the polycyclic main cores of (-)-strychnosplendine, (+)-isosplendine, and (+)-malagashanol, three other indole alkaloids, are reported.Guidelines published in 2016 provide a revised definition of sepsis life-threatening organ dysfunction caused by a dysregulated host response to infection. The guidelines define septic shock as sepsis with circulatory, cellular, and metabolic dysfunction that is associated with a higher risk of mortality. The measurement of serum lactate has been incorporated into the latest septic shock definition. The guidelines recommend the Sequential Organ Failure Assessment (original and quick versions) as an important tool for early diagnosis. Respiratory, gastrointestinal, genitourinary, and skin and soft tissue infections are the most common sources of sepsis. Pneumonia is the most common cause of sepsis. Although many patients with sepsis have fever, the clinical manifestation can be subtle, particularly in older patients and those who are immunocompromised. Initial evaluation of patients with suspected sepsis includes basic laboratory tests, cultures, imaging studies as indicated, and sepsis biomarkers such as procalcitonin and lactate levels.